Filter-press and method of preventing the oxidation of the filtrate in the containers thereof.



I L. 0. MILLS. FILTER PRESS AND METHOD OF PREVENTING THE OXIDATION OF THE FILTRATE IN THE CONTAINERS THEREOF.

APPLICATION FILED DEC.24, I9l2. 1,236,737.

Patented Aug. 14, 1917.

a and the treatment of-jsuchmater-i UNITED STATES PATENT OFFICE.

LOUIS DAVID MILLS, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO MERRILL METALLURGICAL COMPANY, A CORPORATION OF CALIFORNIA.

FILTER-PRESS AND METHOD OF PREVENTING THE OXIDATION OF THE FILTRATE IN THE CONTAINERS THEREOF.

' s ecification! Letters mat.

Patented Aug. 14, 1917.

Application filed December a4, 1912. Serial No. 738,449.

To all whom it may concern:

citizen of the United States of America, and

si dent of the city and county of San Fran- Presses and Methods or Preventing the Oxidation of the Filtrate in the Containers- Thereof, of which the following is aspeclfi-f cation, a

in which the precipitation and collection material from hydrometallurgicallso fected. The principalobjectof the preset! invention is to overcome certain disadvaii 7 tages which arelfound to exist in practice in conducting the process aforesaid in othe types of filter presses.

In various Letters Patent which 1 been grantedjor such other types of filte presses, the advantagesof maintaining 're' ducing conditions throughoutvthe; precipl ta-r tion and collection of the precipitate aredescribed; and such presses provide for the maintenance, by various suitable devices, of 7 these reducing conditions up to the time that the mixture of solution, precipitant and f precipitate, is delivered tothe inletchannel of the pressure filter described and claimed a I y sub ect of the present invention may be termed an upward deliver be best understood by a re erence to the acas ab Now the mechanical all times to keep the container filled duringthe operation of the filter press; second, some-mixtures filter so freely that the bot-- of the filtrate results in the tom dischar press not being kept full of the mixture of filterable and unfilterable matter; third,-.it is sco, State of California, have invented certain new and useful Improvements 1nvF1lterdefects which have I developed in the types of apparatus de scribed, for example, in Letters Patent of The filter plates are "type of construction as 's own in the views which show the form of filter plate adapted not'always'possible in the practical operation' of reduction works to deliver to the filter' press continuously at sufficientfeed of "the mixture of filterable and unfilterable material to keep it full, and, fourth, when the filter press is not in use the practical difficulty of preventing the discharge cocks from leaking results in at least a portion of the liquid filterable portion draining out. The

' result of any of the above mechanical defects is that oxygen of the atmosphere occupies the spacethat should be filled with v the mixture or its filterable component, and the effect of the contact of the'oxyge'n with "the mixture orits unfilterable component is "tooxidize the precipitate and precipitant ontained in the press and thus decrease the pfaprecipitation, as that portion of the r precipitation.

unearthe topof a side of the plate a pn vof the filtrate will drain. out of the r'po'rtion of the container and result in -tliefoicidation of the precipitant and precipifate therein.

w N have discovered that when the filtrate is discharged above the top of the plate the container is kept complete filled with solution not only during the periods of precipitation-but also during the intervals between such periods whenthe press is not in operation. y

The type of filter plates forming the plate and will from the top; Fig. 2 shows the invention applied to a rectangular plate; Fig. 3, to a "curvilinear plate, and Fig. 4, a view of a modification.

Similar letters refer to similari parts throughout the several views.

referably ofthe .to be used in connection with the forms of container of the character of those most in general use. Each filter plate is provided with an opening 05 through which theme terial ;to' be, filtered is introduced, which att'e which is oxidized is unavailable for I't'h the use of a port'oropening fiic'iency" of precipitation and increase the channel or inlet is of the same general character as that in the containers and becomes continuous when-the varlous arts are put together 'in the filter press, an which, with ran ement descri W. errill in Letters Patent of the United plates, as shown in Figs. 1 to 4 inclusive,

' plate.

which are provided for the efiluent liquids,

vapors or gases. They terminate in the form shown in Fig. 1- in a ptil'pe bent in the form of a goose neck which 1 launder or trough o of suitable dimensions.

Fig. 2 shows the goose neck attached to a rectangular plate. Fig. 4 shows it attached to a curvilinear plate. Fig. 4 shows thegoose neck slightly changed in form, namely, bent at two points at right angles, and provided with a discharge cock controlling the discharge therefrom. The goose neck, or the pipe, or the form of structure shown in Fig. 4 may be attached to a filter plate in any convenient manner, and maybe placed at any convenient position on the topof the The efiect of raising the discharge on each plate and of course on the hea s also, as efi'ected by the hereinbefore described device, is to prevent the upper position of the press from standing empty and oxidizin each time that the press'is shut down, w ich is the result of the impracticability of maintaining absolutely continuous filtration during precipitation. In these cases the upper portion of the filter cloth is found to be nearlybare of precipitant, or

escribed, when placed topreferably the are scharges in a if anydprecipitant is found, it is usually in an 0x1 1zed'cond1t1on.

I claim as my invention:

1. The hereinbefore described method-of preventingthe oxidation of the precipitate and recipitant in the containers of opened topischarge filter presses in which hydro metallurgical precipitation and filtration is effected, by causingthe filtrate to be discharged from each filter plate at a point above the uppermost level of the mixture efiected, by causin' the filtrate to be separately discharged rom each filter plate at a point above the uppermost level of the mixture within the press, whereby, the admission of air into the containers is prevented.

3. A hydrometallur 'cal filter press comprising a pluralit of lter plates each-plate having an open discharge pipe with its dis charge end above the level of the top of the filtering surface of the plate.

4. A hydrometallurgcal filter press compgising a pluralifiy of her plates, each plate ving an open ischarge pi e with its discharge cnd above the levelo the top of the filtering surface of the late, and each discharge pipe being provi ed with a stop cook.

In testimony, that I claim the foregoing as my invention, 1 have signed my name in presence of two witnesses,this twenty-first day ofi November 1912.

LOUIS DAVID MILLS.

Witnesses:

L. F. Hmmmn, C. B. Hrmnnnson. 

